1. Field of the Invention
The present invention relates to an apparatus for sampling filter cigarettes for quality inspection during the manufacture of the filter cigarettes.
2. Description of the Related Art
When a cigarette rod, which is twice as long as a cigarette, is supplied to a filter cigarette manufacturing apparatus or a so-called filter attachment, it is cut into two equal parts or individual cigarettes. Then, a filter plug is supplied between these cigarettes. A paper piece is wound around the two cigarettes and the plug to connect them, thus forming a double filter cigarette. Thereafter, the double filter cigarette is cut in the center into individual filter cigarettes.
As these processes are executed, cigarette rods, cigarettes, and double filter cigarettes are transported continuously in the filter attachment.
The filter attachment is provided with a filter cigarette sampling apparatus for periodical quality inspection. Examples of this sampling apparatus are described in Published Unexamined Japanese Patent Applications Nos. 59-162868 and 1-277478.
The sampling apparatus described in Published Unexamined Japanese Patent Applications No. 59-162868 comprises a sampling drum for taking out filter cigarettes by continuous suction during transportation, while the one described in Published Unexamined Japanese Patent Applications No. 1-277478 comprises a sampling drum for taking out filter cigarettes by selective suction.
In the case of the former sampling apparatus, the filter cigarettes are continuously sampled as they are transported, so that the filter cigarette sampling may possibly be subject to a bias.
In the latter case, the selective suction of the filter cigarettes during transportation requires proper intermittent supply of suction pressure to the sampling drum, and a solenoid valve is used for this intermittent supply. Since the sampling drum and the solenoid valve are located at a distance from each other, however, a time lag is entailed before a substantial suction pressure is supplied to the sampling drum even though the valve is opened. Accordingly, proper control of the timing for the switching operation of the solenoid valve, which is required by accurate filter cigarette sampling, is very difficult. The higher the operating speed of the filter attachment, that is, the higher the speed of filter cigarette transportation in the filter attachment, moreover, the more carefully the lag of the switching operation of the solenoid valve itself should be considered for appropriate filter cigarette sampling.